The present invention relates to suspension thrust bearings used in particular in telescopic suspension arms of steered wheels of automobile vehicles.
A suspension thrust bearing generally includes a top race and a bottom race between which are disposed rolling bodies in the form of balls or rollers.
The invention relates more particularly to suspension thrust bearings including at least one synthetic material cap in contact with one of the two races of the bearing.
The suspension thrust bearing is disposed at the top of the suspension arm, between a generally metallic bottom cup, serving also as a seat for a suspension spring, and a top member fastened to the body of the vehicle. This is known in the art. The suspension spring is installed around the piston rod of the damper, the end of which is fastened to an elastic support block. The suspension thrust bearing allows rotation between the bearing cup of the spring, which can rotate, and the elastic support block, which is fixed to the body of the vehicle. The suspension thrust bearing also transmits axial forces between the spring and the body of the vehicle. Relative angular movement between the spring bearing cup and the elastic support block results from turning of the steered wheel and/or compression of the suspension spring. The top race of the bearing can be equipped with a metal band bent over said race and clamped to said top member fastened to the body of the vehicle. See French patent No. 2 665 494, for example. However, it is difficult to control the clamping of the band into the housing of the top member because of manufacturing tolerances.
A device employing one or two synthetic material caps can be used, as described in the document U.S. Pat. No. 4,995,737 or EP-A-390 331, each cap capping a race and having axial retaining means cooperating with the other cap. The caps are generally made from synthetic material charged with glass fibers to give them the necessary strength and stiffness. Synthetic material caps transmit and distribute forces between the bearing and the adjacent members. They also standardize the dimensions of the bearing races, i.e. they enable the same races to be used for different applications merely by modifying the external geometry of the caps.
The invention proposes a suspension thrust bearing forming a compact assembly adapted to be easily manipulated and transported without risk of accidental loss of any of its components.
The suspension thrust bearing conforming to one aspect of the invention includes a first race, a second race, a row of rolling bodies disposed between the two races, a first cap in contact with the first race, and a first cup in contact with the first cap. The first cap includes integral axial retention means for retaining the first cup.
This provides a simple subassembly, consisting of the suspension thrust bearing and the top cup, that cannot come apart while it is being manipulated and is easy to manipulate, transport and finally mount on the vehicle.
In one embodiment of the invention the axial retention means of the first cap include an annular lip force-fitted over a cylindrical outside surface or a bore of the first cup.
In another embodiment of the invention the axial retention means of the first cap include a plurality of tongues interfering with a cylindrical outside surface or a bore of the first cup.
The bearing advantageously includes a second cap in contact with the second race. The first cap includes axial fastening means for fastening it to the second cap.
In one embodiment of the invention the axial fastening means of the first cap for fastening it to the second cap include an annular rib and the second cap is adapted to cooperate with the rib, for example another rib of complementary shape.
In one embodiment of the invention the bearing includes a second cap fastened to the second race and a second cup in contact with the second cap. The second cap includes axial fastening means for fastening it to the second cup.
In one embodiment of the invention the axial fastening means of the second cap for fastening it to the second cup include a plurality of hooks interfering with a surface of the second cup.
The first and second races are advantageously made from thin sheet metal. The first and second races can consist of a simple annulus whose cross section is circular-arc-shaped.
A suspension thrust bearing is obtained whose overall size in the axial and radial directions is not changed compared to prior art bearings, which provides an excellent seal and which includes means for fastening its various members together.
The invention will be better understood and other advantages will become apparent on reading the detailed description of a few embodiments provided by way of non-limiting example and shown in the accompanying drawings, in which: